2005 MITSUBISHI LANCER ECU

55-1
GROUP 55
HEATER, AIR
CONDITIONER AND
VENTILATION
CONTENTS
SERVICE SPECIFICATIONS . . . . . . .55-3
LUBRICANTS . . . . . . . . . . . . . . . . . .55-3
SPECIAL TOOLS . . . . . . . . . . . . . . . .55-4
TROUBLESHOOTING . . . . . . . . . . . .55-5DIAGNOSIS TROUBLESHOOTING
FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55-5
SYMPTOM CHART . . . . . . . . . . . . . . . . . . . 55-5
SYMPTOM PROCEDURES . . . . . . . . . . . . 55-5
CHECK AT ECU TERMINAL . . . . 55-67
CHECK AT ECU TERMINAL . . . . 55-68
Continued on next page
W ARNING S RE GA RDING S E RV ICIN G O F SUP P LE MEN TAL R ES TRAI NT S Y ST EM (SRS ) E Q UIP PE D VE HICL ES
I mp roper se rvi ce o r m ai nte na nce of a ny c omp onent of the SRS , or an y SRS -re la te d c om pone nt, ca n le a d to
personal injury or death to service personnel (from inadvertent firing of the air bag) or to the driver (from
re nd er ing the S RS inop er ati ve).
S e rvic e or m ai nten anc e of an y SRS com pon ent or SRS -re late d com pone nt m ust be pe rfor me d only a t an
authorized MITSUBISHI dealer.
M ITSUBISHI dealer p erso nnel must thoroughly review th is man ual, and esp ecially its GROU P 52B - Su pplemen tal
Restraint System (SR S) b efore beginn ing an y service o r maintenance of any comp onent of th e SRS or any SRS-
rel ated com ponent.
NOTE
The SRS includes the following components: front impact sens ors , SRS-ECU, SRS warning lamp, air bag module, c lock spring
and interconnecting wiring. Other SRS-related components (that may have to be remov ed/installed in connection with SRS
service or maintenance) are indicated in the table of c ontents by an asterisk (*).

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-5
TROUBLESHOOTING
DIAGNOSIS TROUBLESHOOTING FLOWM1552009600364
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points P.00-5.
SYMPTOM CHARTM1552009900611
NOTE: Refer to GROUP 14, Troubleshooting P.14-5
for the condenser fan.
SYMPTOM PROCEDURES
INSPECTION PROCEDURE 1: When the Ignition Switch is "ON" the A/C does not Operate.
COMMENTS ON TROUBLE SYMPTOM
The blower system or the compressor system may
be defective if there is no cool air coming from the
spit hole.
TROUBLESHOOTING HINTS
•Malfunction of blower motor
•Malfunction of A/C compressor
DIAGNOSIS
Check that the blower motor operation when the
blower switch is moved to the "HI" position.
(1) Turn the ignition switch to the "ON" position.
(2) Turn the blower switch to the "HI" position.
Q: Does the blower motor operate when the blower
switch is moved to the "HI" position?
YES :
Refer to Inspection procedure 3
"When the A/C is operating, temperature
inside the passenger compartment does not
decrease (cool air is not emitted).
P.55-11."
YES : Refer to Inspection procedure 4
"When the A/C is operating, temperature
inside the passenger compartment does not
decrease (cool air is not emitted).
P.55-20."
NO : Refer to Inspection procedure 5 "Blower fan
and motor do not turn P.55-29." Symptom Inspection
ProcedureReference
Page
When the ignition switch is "ON" the A/C does not operate. 1
P.55-5
Inside/outside air selection is not possible. 2
P.55-6
When the A/C is operating, temperature inside the passenger
compartment does not decrease (cool air is not emitted). 3
P.55-11
When the A/C is operating, temperature inside the passenger
compartment does not decrease (cool air is not emitted). 4
P.55-20
Blower fan and motor do not turn. 5
P.55-29
Blower air amount cannot be changed. 6
P.55-39
Rear window defogger function does not operate. 7
P.55-42
Rear window defogger Timer function does not operate. 8
P.55-52
Malfunction of the A/C-ECU power supply system. 9
P.55-53
Malfunction of the A/C-ECU power supply system. 10
P.55-56
A/C compressor power supply system. 11
P.55-59
Condenser Fan does not operate. 12 Refer to
GROUP 14
P.14-5

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-6
INSPECTION PROCEDURE 2: Inside/Outside Air Selection is not possible.
COMMENTS ON TROUBLE SYMPTOM
If the inside/outside air selection damper motor does
not operate normally, the inside/outside air selection
damper motor system may be defective.
TROUBLESHOOTING HINTS
•Malfunction of the inside/outside air selection
damper motor
•Damaged the wiring harness or connectors
•Malfunction of the manual air conditioner control
panel (A/C-ECU)
IGNITION
SWITCH (IG2)
OUTSIDE/INSIDE
AIR SELECTION
DAMPER CONTROL MOTOR
A/C-ECU
HEATER CONTROL PANEL
Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet

Outside/Inside Air Selection Damper Control Motor Circuit

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-7
DIAGNOSIS
STEP 1. Check the defogger and A/C operations.
Q: Do the defogger and A/C work normally?
YES :
Go to Step 2.
NO : Refer to Inspection procedure 9
"Malfunction of the A/C-ECU power supply
system P.55-53 ."
NO : Refer to Inspection procedure 10
"Malfunction of the A/C-ECU power supply
system P.55-56 ."
STEP 2. Connector check: C-107 outside/inside
air selection damper control motor connector
Q: Is the check result normal?
YES :
Go to Step 3.
NO : Repair the connector.
STEP 3. Voltage measurement at the C-107
outside/inside air selection damper control motor
connector.
(1) Disconnect the connector, and measure at the
wiring harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 7 and
body earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 5.
NO : Go to Step 4.
AC303804
Connector: C-107

AD
Harness side
AC303816
Connector: C-107
AI

Harness side
AC303804
Connector: C-107

AD
Harness side
AC303816
Connector: C-107
AI

Harness side
AC301541
6 2
7
3
5
4
1
EF
Connector C-107
(Harness side)

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-9
Prior to the wiring harness inspection, check
intermediate connector C-106, joint connector C-35,
junction block connectors C-209 and C-210, and
repair if necessary.
•Check the outside/inside air selection damper
control motor power supply line for open circuit.
Q: Is the check result normal?
YES :
The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction P.00-5).
NO : Repair the wiring harness.
STEP 5. Connector check: C-139 A/C-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 6.
YES : Go to Step 7.
NO : Repair the connector.
AC303823
Connectors: C-209, C-210
AE
C-210
Junction block (front view)
C-209
C-209
Harness side
1016
145
12134117 238 9
C-210
Harness side
4 65321
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303818
Connector: C-139

AJ
Harness side
C-139 (B)
11 12657 8 9 103 421

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-10
STEP 6. Check the wiring harness between C-107
outside/inside air selection damper control motor
connector (terminals 6 and 4) and C-139 A/C-ECU
connector (terminals 2 and 3).
NOTE: Prior to the wiring harness inspection, check
intermediate connector C-106, and repair if
necessary.
•Check the outside/inside air selection damper
control motor earth line for open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 8.
NO : Repair the wiring harness.
STEP 7. Check the wiring harness between C-107
outside/inside air selection damper control motor
connector (terminals 6 and 4) and C-139 A/C-ECU
connector (terminals 10 and 11).
NOTE: Prior to the wiring harness inspection, check
intermediate connector C-106, and repair if
necessary.
•Check the outside/inside air selection damper
control motor earth line for open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 8.
NO : Repair the wiring harness.
STEP 8. Check the outside/inside air selection
damper control motor
Refer to P.55-86.
Q: Does outside/inside air selection damper control
motor work normally?
YES :
Replace the manual air conditioner control
panel (A/C-ECU).
NO : Replace the outside/inside air selection
damper control motor.
AC303804AK
C-106
Harness side
C-107
Connectors: C-106, C-107

C-106C-107
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303816
Connectors: C-106, C-107
AO
C-107
C-106
Harness side
C-107C-106
AC303818
Connector: C-139

AJ
Harness side
C-139 (B)
11 12657 8 9 103 421

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-11
INSPECTION PROCEDURE 3: When the A/C is Operating, Temperature Inside the Passenger
Compartment does not Decrease (Cool Air is not Emitted).
ENGINE-ECU
A/C-ECUDUAL
PRESSURE
SWITCH
RESISTOR ENGINE-A/T-ECU
HEATER CONTROL PANEL
Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet
AIR THERMO
SENSOR
NOTEM/T
A/T
A/C-ECU System Circuit

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-12
COMMENTS ON TROUBLE SYMPTOM
If cool air is not distributed when the A/C switch is on,
the air thermo sensor or the A/C compressor relay
system may be defective.
TROUBLESHOOTING HINTS
•Improper amount of refrigerant
•Malfunction of the air thermo sensor
•Malfunction of the dual pressure switch
•Malfunction of the A/C compressor relay
•Malfunction of the A/C refrigerant temperature
switch
•Malfunction of the magnetic clutch
•Malfunction of the manual air conditioner control
panel (A/C-ECU)
•Damaged the wiring harness or connectors
•Malfunction of the engine-ECU or the
engine-A/T-ECU
DIAGNOSIS
STEP 1. Check the defogger and outside/inside
air selection damper control motor operation.
Q: Do the defogger and outside/inside air selection
damper control motor work normally?
YES :
Go to Step 2.
NO : Refer to Inspection procedure 9
"Malfunction of the A/C-ECU power supply
system P.55-53 ."
STEP 2. Check the blower motor operation.
Q: Does the blower motor work normally?
YES :
Go to Step 3.
NO : Refer to Inspection procedure 5 "Blower fan
and motor do not turn P.55-29."
STEP 3. Check the A/C compressor.
Check the A/C compressor for compressor oil leaks.
Q: Is the check result satisfactory?
YES :
Go to Step 4.
NO : Replace the A/C compressor or the
expansion valve.
STEP 4. Connector check: B-114 A/C compressor
connector and C-123 engine-ECU connector
or C-122 engine-A/T-ECU connector
Q: Is the check result normal?
YES :
Go to Step 5.
NO : Repair the connector.
AC303782
Connector: B-114
<4G1-L.H.D.>
AC
Harness side
B-114 (B)
AC303790
Connector: B-114
<4G6-L.H.D.>
AC
Harness side
B-114 (B)
AC303805
Connectors: C-122 , C-123

C-122 (GR)
C-123 (Y)
C-122 Harness side
C-123
AE